A dosage of 3mg of radioactive iodine is administered for some forms of thyroid cancer. The half-life of Iodine is 8 days. If the maximum permissible level of iodine in the thyroid is 5 mgs, what is the minimum number of days before dosage of 3mg can be given?

Question

alekos · Answer

any ideas? have you tried this?

anonymous · Answer

Yes, I would use the formula which is m(t)= Ce^kt. But I don't know how to find k to make my equation.

anonymous · Answer

find k by knowing that in t=8 days, the amount of m is half what you started with

use k with the equation for t to find how long the 3 mg need to decay to become 2 mg so that the total dose of 2 + 3 mg given that day does not exceed 5 mg.

anonymous · Answer

the answer for the first part is$$y= (\frac{ 1 }{ 8}\ln \frac{ 1 }{ 2 }) y$$. I don't understand how they got that.

alekos · Answer

that equation cant be right because you have y on both sides?

alekos · Answer

go with douglas' suggestion, he's right

anonymous · Answer

I meant the (y)'. Because I'm suppose to find a differential equation. But I understand now. Thanks for your help